This invention relates to a method and system for registering transmitter identifications (IDs) in a pneumatic tire pressure monitoring system, also relates to a method and system for identifying transmitters, and further relates to a pneumatic tire pressure monitoring system and its apparatus, and also relates to a pneumatic tire pressure monitoring program.
A pneumatic tire pressure monitoring system is conventionally known as including a plurality of transmitters incorporating pressure sensors attached to respective tires of an automotive vehicle as well as a receiver provided in a vehicle body for receiving a radio signal carrying pressure data transmitted from each transmitter. The conventional pneumatic tire pressure monitoring system has the capability of detecting abnormal reduction in the air pressure of each tire based on the pressure data sent from the associated transmitter. According to this conventional pneumatic tire pressure monitoring system, the receiver stores individual IDs assigned to the transmitters attached to the tires belonging to its own vehicle. When a transmitter signal is received, the receiver executes ID checking for discriminating the signals sent from the transmitters attached to the tires of its own vehicle from signals sent from transmitters attached to tires of other vehicles.
In general, an automotive vehicle is equipped with a total of five tires including a spare tire. Among these five tires, the spare tire requires no monitoring of air pressure to be performed by the pneumatic tire pressure monitoring system. In other words, the monitoring operation by the pneumatic tire pressure monitoring system should be executed for the remaining four tires actually installed on vehicle wheels. To this end, the objectives for ID registration are limited to the tires actually installed on the vehicle wheels. In an event that any one of four actually driven tires is punctured and replaced by the spare tire, the ID assigned to the punctured tire is deleted and withdrawn from registration while the ID assigned to the spare tire is newly registered as one of registered IDs.
Reregistering the IDs is time-consuming and complicated for a worker or a user who replaces the punctured tire by the spare tire. In some cases, the worker may forget or fail to register the transmitter ID of the spare tire to the receiver. In this case, the pneumatic tire pressure monitoring system cannot operate properly due to miss or failure in registering the transmitter ID of the spare tire.
To eliminate this drawback, it may be possible that all of transmitter IDs of five tires including the spare tire is registered in advance in the receiver register. However, in this case, another problem occurs unless the transmitter ID of the punctured tire is deleted from the objectives of the monitoring. Namely, the pneumatic tire pressure monitoring system will continuously generate a warning based on the pressured data sent from the transmitter associated with the punctured tire. Thus, the warning does not stop even after the punctured tire is replaced by the spare tire. In other words, it was inevitably required to reregister the transmitter IDs of the tires actually installed on the vehicle wheels after the exchange of tires is finished.
Japanese Patent No. 2774959, corresponding to the U.S. Pat. No. 5,612,671, discloses a low tire pressure warning system which has a learning capability of automatically registering the transmitter IDs of the tires. According to this system, the receiver has an ID check table listing the transmitter IDs of four tires belonging to its own vehicle. An ID received together with pressure data is compared with the registered IDs in the table to judge whether or not the received pressure data originate from any one of the transmitters attached to the tires of its own vehicle. The presence of any abnormality in the tire pressure is judged based on the received pressure data. And, a warning is generated when the abnormality is found. If a new ID is received together with normal pressure data, the receiver adds the newly received ID into the ID check table. On the contrary, when no signal is received from the transmitter having one of the registered IDs, the ID of this transmitter is deleted from the ID check table.
According to above prior art, the warning system will serve for automatically registering the transmitter IDs of four rotating or driven tires actually installed on vehicle wheels only when a spare tire is accommodated in a trunk room of a sedan-type car because the trunk room can provide sufficient shielding against radio waves. In other words, the system cannot operate as intended when it is installed in an RV-type car which mounts a spare tire on the outer surface (usually, on the rear door) of a vehicle body. If a punctured tire is mounted on the back of the RV-type car, the abnormal pressure signal will be continuously transmitted from the punctured tire to the receiver. According, the warning operation will be erroneously continued.